B & S 17.5 HP Problem

[Craftsman Garage]

On these engines, this is a very frequent problem that I have run into and it is always caused by a bad compression release

 

[Auto Doc's]

I have replaced a few camshafts due to a bad compression release mechanism, but most of the time owners don't want to fix them. I have 3 of them right now in my scrap mower collection.

I don't trust the replacement cams offered enough to invest the money and fix them myself. I have had too many repeat failures with these.

 

[Craftsman Garage]

They don't call them "Breaks and scrapem'" for nothing. If they break, scrap them, because they are not worth fixing because they will just break again.

 

[Auto Doc's]

I have a lot of older Briggs & Stratton engines still going strong, most are the much older flat head design.

For longevity, I gotten the best life out of Kohler engines when it comes to riders.

Honda is a close second when it comes to other power equipment.

The way emissions laws are going, they may all be scrapyard bound in the near future

 

[Hammermechanicman]

Thaks for the response. Yes, I have no problem there. On advice gained on this site I have adjusted the valves but the problem persists. I guess it is the compression release on the cam. When I start the tractor have been rotating the engine counterclockwise a ways and that allows it to get enough momentum to start.

I have a couple customers with bad cams on old craftsman mowers. Not worth having me put cams in them and i showed them the turn bsckwards till it hits compression and then it will crank. They think i am some kind of magician LOL

 

[Craftsman Garage]

I love those old flathead engines. One time I was able to run one of those 3 hp flat heads on a edger for about 50 hours without oil! It had an oil leak that I did not notice

 

[Forest#2]

Instead of immediately loosening the INTAKE valve adjuster and fiddling around with taking the INTAKE valve lash to minimum specs to check for compression release I just use feeler gauge under the rocker valve stem and take the lash to minimum using the gauge and check for crank through.
Saves lots of time W/O doing the actual lash adjustment at first.

 

[Auto Doc's]

Gee! Everyone wants to sound scientific.

Keep it simple.

Pull the plug and remove the rocker cover. Rotate the engine by hand in the normal cranking rotation and watch the intake valve movement. If the compression release is working, there be a quick bump of the intake valve before it opens normally. If the Intake valve operates all in one motion just like the exhaust valve, the compression release is not operating.